Twice as many voters prefer Cameron to Brown as PM

The Conservatives are 15% ahead in an ICM poll for tomorrow’s Guardian. The Guardian is choosing to lead on the fact that twice as many voters prefer Cameron to Brown as PM:

"Asked to say which of Cameron and Brown would make the best prime minister, 42% of those polled say Cameron, 21% say Brown and 23% say neither. When voters are asked to choose between Cameron and Miliband, 40% say Cameron, 19% say Miliband and 18% say neither."